Mocking an Throwable interface produces an error

[Julien BIANCHI]

Given we have:

<?php

interface MyThrowable extends Throwable {
    //...
}

If we try to mock this interface, it results in an error:

Class MyThrowable cannot implement interface Throwable, extend Exception or Error instead

[Grummfy]

probably solved in version 4.0.0 with the change made on #843